The present invention relates to switching devices for controlling vehicle headlamps and fog lamps. Heretofore, switches employed for controlling high and low beam headlamps and providing a flash-to-pass function and also incorporating the switching function for the fog lamps have been actuated by a stalk or lever mounted on the steering column. Typically, movement of the stalk or lever in the direction coinciding with the axis of the steering column has been employed for changing the headlamp from the low beam to the high beam mode and simultaneously switching off the fog lamps in the event same were on at the time of the user actuating the stalk. Heretofore, the switching contacts employed for effecting the switching functions were of relatively low current carrying capacity in order to render the switch compact and inexpensive; and, consequently, the switching contacts were only used to energize relays for switching the current for the headlamps and fog lamps.
Referring to FIG. 11, a schematic for a prior art flash-to-pass headlamp switching system is illustrated in which a stalk operated switch assembly 1 is connected to the vehicle power supply at terminal 2 which is connected through junction 3 to the common terminal 4 of a single pole double throw (SPDT) switch having a side contact 5 which is connected through connector terminal 6 to a low beam headlamp. The opposite side contact 7 of the SPDT switch is connected through connector terminal 8 to an input terminal 9 of a relay 10. Side contact 7 is also connected to a side contact 11 of a single pole single throw switch having user moveable actuator 12 for, upon closing of the switch, connecting side terminal 11 to an opposite side terminal 13 which is connected to the power junction 3.
The input terminal 9 of relay 10 is connected to one lead of a relay coil 14 which has the opposite lead connected through terminal 15 to ground. A resistor R is provided in parallel with the coil. A power input terminal 16 is connected to the vehicle power supply and to the common terminal 17 of a second single pole double throw switch having one side contact 18 thereof connected through an output terminal 19 to a vehicle fog lamp. A second side contact 20 is disposed opposite the switch contact 18 and is connected through connector terminal 21 the vehicle high beam lamp. Thus, user movement of switch actuator 12, which may be effected by a steering column mounted stalk lever, also causes switch member 4 to break the power to the low beam headlamp and apply power to the high beam input of the relay 10; and, simultaneously the switch actuator 4 is latched to secure power to the high beam input to the relay. Energization of relay coil 14 causes switch member 17 to break the current to the fog lamps and switch power to the high beam headlamp.
It has been desired to maintain the simple single stroke lever actuation of the steering column mounted stalk lever for performing the high beam switching and flash-to-pass function; and, thus limited switching motion is available to perform the various switching functions required for flash-to-pass operation.
In the high-volume, mass-production of motor vehicles, it has been desired to minimize the cost of electrical switching functions and thus it has been desired to find a way or means of eliminating the relays required for the high beam and flash-to-pass switching functions of the headlamps and fog lamps and direct switching of the head lamp current yet retain the use of the steering column mounted stalk lever for user actuation of the flash-to-pass function.